The present invention relates to an antenna adjuster for adjusting the position, i.e., azimuth and elevation angles, of an antenna relative to a pole which the antenna is secured to and, more particularly, to an antenna adjuster which permits ready and accurate adjustment of the antenna with a simple, small-size and light-weight structure and is suited for fine adjustment of relatively small-size parabola antennas among the microwave antennas.
Among well-known antenna adjusters of this type are one for aerials (or antennas) parabola reflectors, as disclosed in Japanese Laid-Open Utility Model Publication No. 61-154003, and one as disclosed in Japanese Laid-Open Patent Publication No. 61-288502.
FIGS. 6 to 8 are views an example of the antenna adjusters disclosed in Japanese Laid-Open Utility Model Publication No. 61-154003. FIG. 6 is a schematic front view showing the antenna adjuster. FIG. 7 is a perspective view showing an essential part of the antenna adjuster shown in FIG. 6. FIG. 8 is a fragmentary side view showing the antenna adjuster shown in FIG. 6.
The illustrated antenna adjuster as described in Japanese Laid-Open Utility Model Publication No. 61-154003, comprises an arm 101 rotatably mounted on a pole 200 supporting the antenna 100 and secured to the pole 200 at an adequate position thereof, a horizontally rotatable base 102 mounted on the arm 101 and rotatable about an axis 107 of rotation in the azimuth angle directions, and a tiltable base 103 mounted on side walls of the horizontally rotatable base 102 and tiltable about horizontal axis 104, 105 of rotation parallel to the arm 101. The antenna 100 is mounted on the tiltable base 103.
A crank mechanism 110 is secured to the tiltable base 103, and a screw drive mechanism 111 is screwed to the crank mechanism 110. By turning a handle 111a a crank mechanism 110 is operated to cause rotation of the tiltable base 103 in the azimuth angle directions.
A crank mechanism 120 is secured to the horizontally rotatable base 102, and a screw drive mechanism 121 is screwed to the crank mechanism 120. By turning a handle 121a a crank mechanism 120 is operated to cause rotation of the horizontally rotatable base 102 in the azimuth angle directions.
With the above construction of the antenna adjuster disclosed in Japanese Laid-Open Utility Model Publication No. 61-154003, the antenna 100 can be driven by the crank mechanisms 110 and 120 and screw drive mechanisms 111 and 121 for rotation about the axis 104 and 105 as shown in FIG. 8 in the elevation angle directions and rotation about the axis 107 as shown in FIG. 7 in the azimuth angle directions.
In FIG. 6, reference numeral 106 designates a set bolt for securing the tiltable base 103 in position. The set bolt 106 penetrates the horizontally rotatable and tiltable bases 102 and 103, and can secure the tiltable base 103 after position adjustment to the hoirzontally rotatable base 102. The set bolt 106 displaceably penetrates a guide hole 106a formed in the titable base 103.
In FIG. 8, reference numerals 108 and 109 designate set bolts for securing the horizontally rotatable base 102 in position. The set bolts 108 and 109 penetrate the horizontally rotatable base 120 and the arm 101, and can secure the horizontally rotatable base 102 after position adjustment to the arm 101. In FIG. 7, the set bolts 108 and 109 displaceably penetrate guide holes 108a and 109a formed in the arm 101.
In the antenna adjusters disclosed in Japanese Laid-Open Patent Publication No. 61-288502, both the azimuth and elevation angles can be adjusted by operating an adjustment rod having a grip.
FIGS. 9 and 10 show an antenna adjuster shown in Japanese Laid-Open Patent Publication No. 1-288502. FIG. 9 is a perspective view showing the antenna adjuster in use. FIG. 10 is a partly broken-apart, exploded perspective view of the antenna adjuster.
The illustrated antenna adjuster disclosed in Japanese Laid-Open Patent Publication No. 61-288502 comprises a pair of elevation angle adjusting members 210 and 211 supporting the antenna 200 on the back thereof, a box-like housing 220 rotatably supporting the elevation angle adjusting members 210 and 211 and mounted on an antenna support pole (or post) 201 by accommodating the upper end thereof, and a mounting member 230 disposed on the bottom of the housing 220 and secured to the pole 201.
The housing 220 has a box-like shape constituted by side walls 221 and 222, on which the elevation angle adjusting members 210 and 211 are rotatably mounted, a top wall 223, a bottom wall 224 and a back wall 225. The housing 220 has an azimuth angle adjusting rod 240 mounted on one side and an elevation angle adjusting rod 250 mounted on the top.
With this antenna adjuster, for making azimuth angle adjustment, the azimuth angle adjusting rod 240 which is interlocked to the mounting member 230 in the housing 220, is rotated in a predetermined direction.
Rotation of the azimuth angle adjusting rod 240 causes a displacement of a movable nut 231 provided on the mounting member 230 by a threaded portion 240b of the adjusting rod 240.
As a result, the housing 220 is rotated about the pole 201 by a predetermined angle relative to the mounting member 230 secured to the pole 201. In this way, the azimuth angle of the antenna 200 can be adjusted.
For elevation angle adjustment, the elevation angle adjusting rod 250 which is mounted between the top wall 223 of the housing 220 and the elevation angle adjusting member 210, is rotated in a predetermined direction.
Rotation of the elevation angle adjusting rod 250 causes the elevation angle adjusting member 210 to be pushed or pulled by the elevation angle adjusting rod 250, thus causing rotation of the adjusting member 210 in contact with the side wall 221 of the housing 220.
The antenna 200 is rotatably mounted by the elevation angle adjusting members 210 and 211 on the housing 200, while the adjusting members 210 and 211 are coupled to each other via the antenna 200.
Thus, with rotation of the adjusting member 210 on the side of the provision of the elevation angle adjusting rod 250, in contact with the side wall 221 of the housing 220, the other adjusting member 211 is also rotated in contact with the other side wall 222. In this way, the elevation angle of the antenna 200 can be adjusted.
As shown above, the antenna adjuster disclosed in Japanese Laid-Open Patent Publication No. 61-288502 permits antenna adjustment in a simple operation and reliably. In addition, after the adjustment the antenna can be secured in position without possibility of rattling, and it is possible to effectively eliminate a deviation from the adjusted position.
The prior art antenna adjusters as described above, however, had the following problems.
In the antenna adjuster as disclosed in Japanese Laid-Open Utility Model Registration No. 61-154003, the elevation angle adjustment requires operations of adequately loosening the screws 104 and 105 and the set bolt 106, then making adjustment of the antenna with the crank mechanism 110 by operating the crank mechanism 111 with the handle 111a thereof and then re-tightening the screws 104 and 105 and the set bolt 106.
The azimuth angle adjustment also requires operations of adequately loosening the screw 107 and the set bolts 108 and 109, then making adjustment of the antenna with the crank mechanism 120 by operating the screw drive mechanism 121 with the handle 121a thereof and then re-tightening the screw 107 and the set bolts 108 and 109.
The prior art antenna adjuster of this type has many parts to be manipulated and also dictates very cumbersome adjusting operations when adjusting the antenna. Besides, since the crank mechanisms and screw drive mechanisms have complicated structures, the antenna adjuster itself comprises a large number of components, thus leading to structure complication and price as well weight increase.
In another aspect, the antenna support structure readily receives external forces such as wind pressures. With the antenna adjuster as disclosed in Japanese Laid-Open Utility Model Publication No. 61-154003, the arm as the antenna support extends from the pole, and this means that more rigid arm mounting structure is necessary, resulting in further size and weight increases of the antenna adjuster.
The antenna adjuster which has such a complicated and large size structure and requires cumbersome adjusting operations, is undesired from the standpoint of the demands for small size, light weight, ready handling and ready operation of parabola antennas and the like.
A further drawback in this type of prior art antenna adjuster is that no lock mechanism is provided in the handle part of the screw drive mechanism, which is operated when adjusting the antenna. Without any lock mechanism, a deviation from the adjusted antenna position may occur when re-tightening the screws and set bolts after the antenna has been adjusted. This means that it is particularly very difficult to make fine antenna adjustment.
With the antenna adjuster as disclosed in Japanese Laid-Open Patent Publication No. 61-288502, the antenna can be secured in position without possibility of rattling after the adjustment. It is thus possible to effectively eliminate any deviation from the adjusted position as in the case of the above Japanese Laid-Open Utility Model Publication No. 61-154003.
However, again the antenna adjuster as disclosed in Japanese Laid-Open Patent Publication No. 61-288502 is complicated in structure and inevitably tends to be large in size. In this respect, the same problem as in the antenna adjuster as disclosed in the above Japanese Laid-Open Utility Model Publication No. 61-154003 is posed. That is, it is impossible to solve the problem that the antenna adjuster is too elaborate to be used for relatively small antennas.
In addition, the antenna adjuster as disclosed in the Japanese Laid-Open Patent Publication No. 61-288502 is adapted to be installed by fitting the box-like housing on the upper end of the support pole (or post). This means that the installation requires very difficult operations in the case where the post has a high level. Furthermore, the upper end of the pole should have a shape and a size such that the box-like housing can be fitted on it. Moreover, for fitting the housing, the upper end of the pole should always be open.
In actual practice, the shape and size of the pole that permit installation of the box-like antenna adjuster are limited, and pose a problem that the antenna adjuster lack versatility.